It has previously been suggested that joints between bones be fused, that is, surgically immobilized, to promote patient comfort. Thus, U.S. Pat. No. 5,026,373 suggests that a fusion cage be positioned between adjacent vertebrae. Perforations are formed in the cage. The cage is packed with a bone-inducing substance. A method for immobilizing vertebrae is also disclosed in U.S. Pat. No. 5,015,255.
It has previously been suggested that the spatial relationship between portions of a bone in a patient's body be changed to correct deformities. This may be done by removing a wedge-shaped piece of bone in the manner disclosed in U.S. Pat. No. 5,601,565.
Another method of changing the spatial relationship between portions of a bone in a patient's body includes forming a slot in the bone. A forked wedge tool is inserted into the slot. A plate is then placed in a central opening in the forked wedge tool and positioned against the bone. The plate is secured to the bone. The forked wedge tool is then removed from the opening. This method of changing the spatial relationship between portions of a bone in a patient's body is disclosed in U.S. Pat. No. 5,620,448.
A method and apparatus for use in changing a spatial relationship between portions of a bone in a patient's body is also disclosed in co-pending U.S. patent application Ser. No. 09/109,126, filed Jun. 30, 1998 by Peter M. Bonutti and entitled Method And Apparatus For Use In Operating On A Bone. This application discloses the use of a wedge member to expand a slot formed in a bone. The wedge member is porous and may be coated with and/or contain bon growth promoting material. The wedge member may have a configuration which corresponds to a configuration of a portion of the bone which is engaged by the wedge member. Alternatively, the wedge member disclosed in the aforementioned application Ser. No. 09/109,126 may have a circular cross sectional configuration with an external thread convolution to enable the wedge member to be moved into an opening in a bone by rotating the wedge member